In a variety of enclosed environments, as diverse as greenhouses and operating theatres, there is a need for high intensity lighting. A wide range of light bulbs are available to meet these needs: sodium vapour, metal halide and fluorescent lights are among the choices. In each case however, there is a problem.
High intensity lights invariably produce heat. Sometimes a substantial amount of heat. In an enclosed environment, this heat can build up to unacceptable levels. In greenhouses, as in operating theatres, there are stringent temperature as well as lighting constraints that must be addressed independently. Consequently, expensive air circulation and air conditioning systems are often employed to alleviate the problem caused by the excessive heat produced by high intensity lighting.
In addition to the generalized room heating that high intensity lights produce, they give rise to a second related problem. High intensity lights produce a significant amount of infrared radiation that directly warms all of the surrounding illuminated surfaces. In the greenhouse, this typically means that lights can not be positioned too close to the plants that require illumination. The same principle is of course applicable in an operating theatre.
Finally, apart from the infrared emissions that warm surrounding surfaces, high intensity lights typically become excessively hot themselves. The surface temperature of a high intensity bulb rises very quickly to a level that easily burns living tissue that comes into contact with the bulb. This typically makes it necessary to position high intensity bulbs where they will not come into contact with, for example, people or plants. Of course, this may interfere with optimal lighting.
Previously, water-cooled lighting devices have been addressed to solving specific problems inherent to particularly specialized high intensity light sources. U.S. Pat. No. 5,147,130, issued to Watanuki Sep. 15, 1992 provides an innovative cooling device to deal with the excessive heating of optical filters associated with mercury-vapour lamps. U.S. Pat. No. 4,363,080, issued to Sylvester Dec. 7, 1982 relates to a similarly specialized unit for heat dissipation in conjunction with an optical fibre light source used in dental work. These prior art devices are addressed to particular problems inherent in these specialized light sources, they do not teach a solution to the problems mentioned above.